1. Field of the Invention
The present invention relates generally to a relay, and more particularly to an electromagnetic relay having a thinner profile.
2. Description of the Related Art
In a conventional electromagnetic relay, an electromagnet incorporated therein has a general construction wherein a conductive wire is wound to form a coil on a bobbin, as an electrical insulator, with an iron core held therein and the opposite ends of the wire are respectively connected to a pair of coil terminals mounted to the bobbin. In this type of electromagnetic relay, it is known that the coil terminals in the electromagnet are arranged side-by-side in a row extending substantially parallel to the center axis of the coil, and that fixed and movable contact plates forming a make/break contact section in the vicinity of the electromagnet are also arranged side-by-side in a row extending along the coil center axis (see, e.g., Japanese Unexamined Patent Publication (Kokai) No.2000-182496). This arrangement makes it possible to reduce the outside dimension of the electromagnetic relay in, especially, a width direction transverse to the coil center axis, and thus facilitates the reduction in thickness (or width dimension) of the relay.
When the electromagnetic relay having such a thinner profile is produced through the above-described winding process, the end regions of the coil terminals mounted to the bobbin, to which the wire opposite ends are entwined to be mechanically and electrically connected, are previously located at positions allowing the wire ends being readily entwined thereto, i.e., at accessible positions extending transverse to the longitudinal axis of the body of the bobbin so as to project laterally outward from the bobbin. In the winding process, one end of the conductive wire is entwined around the entwining end region of one coil terminal located in the accessible position, so as to be temporarily held thereon. Then, the desired length of the conductive wire is wound around the body of the bobbin to form the coil. Thereafter, another end of the conductive wire is entwined around the entwining end region of another coil terminal located in the accessible position, so as to be temporarily held thereon. Then, the wire opposite ends, temporarily held on the entwining end regions of both coil terminals, are fixed through a soldering or welding process to the corresponding entwining end regions. Finally, the coil terminals are deformed to displace or turn up the entwining end regions from the accessible positions to finished positions where the entwining end regions extend along the lateral side of the coil so as not to project outward from the bobbin. According to this procedure, it is possible to surely perform the winding process and to meet the requirements of a dimensional restriction in, especially, the transverse or width direction of the electromagnetic relay.
However, in the above winding process, a worker""s skill is required for deforming the coil terminals to displace or turn up the entwining end regions, to which the wire ends have been securely connected, from the accessible positions to the finished positions, which may result in increased production costs. In particular, the displacement of the entwining end regions from the accessible positions to the finished positions may generate an excessive tensile stress in the opposite end lengths of the conductive wire, extending between the coil and the entwining end regions, or may result in a loosening in the opposite end lengths of the wire. This excessive tensile stress or loosening in the opposite end lengths of the conductive wire may resultantly cause a breakage of the wire. Also, in a case where the wire ends are fixed to the entwining end regions of the coil terminals through an arc welding, it may be difficult to correctly deform the coil terminals to turn up the entwining end regions into the finished positions after the welding is completed. Therefore, in this case, a soldering is normally performed for fixing the wire ends, which however goes against the general requirements of reduction of solder in manufacturing processes.
Incidentally, in the conventional electromagnetic relay having a thinner profile, a yoke for forming a magnetic path around the coil is securely joined to one axial end of the iron core received in the bobbin, and an armature connected to the yoke through a plate spring in an elastically shiftable manner is disposed to be opposed to another axial end of the iron core, so as to constitute a magnetic-circuit assembly. The magnetic-circuit assembly is then securely mounted to a base as an electrical insulator which in turn supports the fixed and movable contact plates. For this conventional mounting work, the base is provided with a protrusion at a predetermined position while the yoke is provided with a groove capable of tightly receiving the protrusion of the base, and the yoke is press-fitted to the base so as to securely mount the magnetic-circuit assembly to the base.
However, in this structure, a cross-sectional area of the yoke as a magnetic path is reduced at the groove, and thereby a magnetic flux is decreased, which may result in the degradation of magnetic attraction force of the electromagnet and may cause the unstable make/break operation of the electromagnetic relay. If the dimensions of both of the groove in the yoke and the mating protrusion in the base are reduced to solve the above problem, the mounting strength of the magnetic-circuit assembly to the base as well as the structural reliability of the electromagnetic relay may be deteriorated.
It is therefore an object of the present invention to provide an electromagnetic relay having a thinner profile, capable of simplifying a winding process for forming a coil in an electromagnet, while meeting the requirements of a dimensional restriction in, especially, the transverse or width direction of the relay.
It is another object of the present invention to provide an electromagnetic relay having a thinner profile, capable of significantly eliminating the possibility of breakage of a conductive wire of a coil, so as to ensure a high structural reliability.
It is still another object of the present invention to provide an electromagnetic relay, capable of meeting the general requirements of reduction of solder in manufacturing processes.
It is still another object of the present invention to provide an electromagnetic relay, capable of securely mounting a magnetic-circuit assembly to a base without reducing the cross sectional area of a magnetic path, so as to possess stable operating characteristics and a high structural reliability.
In accordance with the present invention, there is provided an electromagnetic relay comprising a base; an electromagnet incorporated to the base; an armature movably arranged relative to the electromagnet; and a contact section incorporated to the base to be actuated by the armature; the electromagnet including a bobbin, a coil having a center axis and carried on the bobbin, and a pair of coil terminals mounted to the bobbin; each of the coil terminals being provided with a first end region and a second end region, extending in respective directions transverse to each other; the coil terminals being disposed in such a manner that respective first end regions extend in a direction transverse to the center axis of the coil to project outward from the bobbin and are arranged side-by-side in a row extending substantially parallel to the center axis, and that respective second end regions extend in a direction parallel to the center axis of the coil to project outward from the bobbin and are arranged side-by-side in a row extending substantially transverse to the center axis; opposite wire ends of the coil being connected respectively to the second end regions.
In this electromagnetic relay, it is preferred that each of the coil terminals is further provided with an intermediate length extending between the first and second end regions, the intermediate length being closely embedded in and integrally fixed to the bobbin.
The coil terminals may have lengths different from each other.
The second end regions of the coil terminals may extend in respective orientations opposite to each other in relation to corresponding first end regions.
The first and second end regions of the coil terminals may extend in respective directions orthogonal to each other.
It is advantageous that the contact section includes a fixed contact plate and a movable contact plate; the fixed contact plate and the movable contact plate being provided respectively with end regions extending in a direction transverse to the center axis of the coil to project outward from the base; the end regions of the fixed and movable contact plates being arranged side-by-side in a row extending substantially parallel to the center axis and aligned to the row of the first end regions of the coil terminals.
The electromagnet may further include an iron core received in the bobbin and disposed along the center axis of the coil, and the electromagnetic relay may further comprise a yoke securely joined to the iron core to form a magnetic path around the coil; the yoke being provided with a protrusion tightly engaged with the base; the electromagnet being fixedly mounted to the base through an interengagement of the protrusion with the base in a press-fitting manner.
The present invention also provides an electromagnetic relay comprising a base; an electromagnet incorporated to the base; a yoke securely joined to the electromagnet to form a magnetic path; and an armature movably supported on the yoke; the yoke being provided with a protrusion tightly engaged with the base; the electromagnet being fixedly mounted to the base through an interengagement of the protrusion with the base in a press-fitting manner.
The present invention also provides an electromagnetic relay comprising an electromagnet including a bobbin, a coil having a center axis and carried on the bobbin, and a pair of coil terminals mounted to the bobbin; each of the coil terminals being provided with a first end region and a second end region, extending in respective directions transverse to each other; the coil terminals being disposed in such a manner that respective first end regions extend in a direction transverse to the center axis of the coil to project outward from the bobbin and are arranged side-by-side in a row extending substantially parallel to the center axis, and that respective second end regions extend in a direction parallel to the center axis of the coil to project outward from the bobbin and are arranged side-by-side in a row extending substantially transverse to the center axis; opposite wire ends of the coil being connected respectively to the second end regions.